Altered Angels: Two Panels from the Immaculate Conception Altarpiece Once in San Francesco Grande, Milan

National Gallery Technical Bulletin volume 32 Leonardo da Vinci: Pupil, Painter and Master

National Gallery Company London

Distributed by Yale University Press

TB32 prelims exLP 10.8.indd 1 12/08/2011 14:40 This edition of the Technical Bulletin has been funded by the American Friends of the National Gallery, London with a generous donation from Mrs Charles Wrightsman

Series editor: Ashok Roy Photographic credits

© National Gallery Company Limited 2011 All photographs reproduced in this Bulletin are © The National Gallery, London unless credited otherwise below. All rights reserved. No part of this publication may be transmitted in any form or by any means, electronic or mechanical, including BRISTOL photocopy, recording, or any storage and retrieval system, without © Photo The National Gallery, London / By Permission of Bristol City prior permission in writing from the publisher. Museum & Art Gallery: fig. 1, p. 79.

Articles published online on the National Gallery website FLORENCE may be downloaded for private study only. Galleria degli Uffizi, Florence © Galleria degli Uffizi, Florence / The Bridgeman Art Library: fig. 29, First published in Great Britain in 2011 by p. 100; fig. 32, p. 102. © Soprintendenza Speciale per il Polo Museale National Gallery Company Limited Fiorentino, Gabinetto Fotografico, Ministero per i Beni e le Attività St Vincent House, 30 Orange Street Culturali: fig. 1, p. 5; fig. 10, p. 11; fig. 13, p. 12; fig. 19, p. 14. © London WC2H 7HH Soprintendenza Speciale per il Polo Museale Fiorentino, Gabinetto Fotografico, Ministero per i Beni e le Attività Culturali / Photo Scala, www.nationalgallery. org.uk Florence: fig. 7, p. 9; fig. 8, p. 9; fig. 9, p. 10; fig. 31, p. 19; fig. 48, p. 27; fig. 49, p. 27. British Library Cataloguing-in-Publication Data. A catalogue record is available from the British Library. Galleria degli Uffizi, Gabinetto Disegni e Stampe, Florence © Soprintendenza Speciale per il Polo Museale Fiorentino, Gabinetto ISBN: 978 1 85709 530 2 Fotografico, Ministero per i Beni e le Attività Culturali: fig. 47, p. 26. ISSN: 0140 7430 1032030 LONDON Victoria and Albert Museum, London © V&A Images / Victoria and Managing Editor: Jan Green Albert Museum, London: fig. 41, p. 108; Windsor Castle, Royal Library. Project Manager: Giselle Sonnenschein The Royal Collection © 2011 Her Majesty Queen Elizabeth II: fig. 35, Editor: Rebecca McKie p. 105. Design: Libanus Press Picture Research: Maria Ranauro and Giulia Ariete MILAN Production: Jane Hyne and Penny Le Tissier Pinacoteca di Brera, Milan © courtesy of the Associazione Amici di Repro by Alta Image Brera: fig. 10, p. 88. Printed in Italy by Conti Tipocolor MUNICH Alte Pinakothek, Bayerische Staatsgemäldesammlungen, Munich © 2011. Photo Scala, Florence / BPK, Bildagentur für Kunst, Kultur und Geschichte, Berlin: fig. 30, p. 18; fig. 35, p. 21; © Photo Cornelia Tilenschi. Doerner Institut, Munich: fig. 15, p. 13; © Photo Sibylle Forster. Bayerische Staatsgemäldesammlungen, Munich: fig. 36, p. 21.

NANTES Musée des Beaux-Arts de Nantes © RMN / Gérard Blot: fig. 41, p. 24; fig. 42, p. 25.

NEW YORK © Copyright All Rights Reserved. Photo courtesy of the Frick Art FRONT COVER Reference Library, New York: fig. 21, p. 96. Leonardo da Vinci, The Virgin of the Rocks (NG 1093), c.1491/2–9 and 1506–8 (detail). PA RIS Musée du Louvre, Paris © RMN / Franck Raux: fig. 2, p. 34; © RMN / TITLE PA GE Gérard Blot: fig. 30, p. 100. Top left: Andrea del Verrocchio, The Virgin and Child with Two Angels (NG 2508), c.1467–9 (detail). VATICAN CITY, ROME Bottom left: Master of the Pala Sforzesca, The Virgin and Child © Photo Vatican Museums: fig. 14, p. 12. with Four Saints and Twelve Devotees (NG 4444), probably c.1490–5 (detail). WA SHINGTON, DC Right: Leonardo da Vinci, The Virgin of the Rocks (NG 1093), Image courtesy of the Board of Trustees, National Gallery of Art, c.1491/2–9 and 1506–8 (detail). Washington, DC.: fig. 27, p. 17; fig. 33, p. 20; fig. 34, p. 20.

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rachel billinge, luke syson and marika spring

The National Gallery’s two panels depicting musician The pictures have a long history of technical angels, An Angel in Green with a Vielle (NG 1661, FIG. 1) examination. Several X-radiographs of details of the and An Angel in Red with a Lute (NG 1662, FIG. 2), were panels were published by Ian Rawlins in 1940, with a purchased in 1898 from Giovanni Melzi, Duca di Lodi, very short commentary stating that the difference in and came with a provenance from the church of San technique between them was evident in these images.3 Francesco Grande in Milan.1 It has never been doubted Later, in his catalogue, Martin Davies described some that they were part of the carved altarpiece created for the of the changes in composition that are visible in the chapel of the Confraternity of the Immaculate Conception X-radiograph image of the Angel in Red, such as the shift abutting that church, for which Leonardo da Vinci, in in the position of the lute and in the angel’s proper partnership with the brothers Ambrogio and Evangelista right arm.4 When the paintings were cleaned in 1974 de Predis, was commissioned to work on the gilding and composite X-radiographs of each painting were made,5 painting.The story of this commission and the subsequent as well as infrared photographs. It was at this time, history of the altarpiece (including the Angels’ place in after removal of the thick, discoloured varnish, that it it) are, however, extremely complicated. Much ink has was noticed that the paint of the grey niches was been spilled on this subject, but it has focused mainly on rather coarse, leading to the suspicion that it was the status of the two great depictions of The Virgin of the not original. A series of samples were examined, described Rocks (Musée du Louvre, Paris, and National Gallery, in an account published by Joyce Plesters in 1975, London) and, although they are always accommodated which confirmed that the grey paint is indeed later in art historians’ attempts to reconstruct the ensemble, repaint, since it lies on dirty, discoloured varnish. It was the Angel panels have been somewhat neglected.2 also established that in the Angel in Green the concealed Both paintings have undergone a number of changes original background includes blue and blue-green since they were created, which relate to the history of the paint, which could be a distant landscape, while the altarpiece as a whole. They no longer appear as they original background of the Angel in Red was quite would have done when fi rst installed in San Francesco different, consisting of pinkish paint.6 A new campaign Grande. Not only have the supports been altered but (as of examinations was begun in 2003 in conjunction has been insufficiently recognised) the grey niches behind with a study of The Virgin of the Rocks. These included the angels are not part of the original scheme. However, the fi rst complete study of the Angels using infrared a considerable amount of their original backgrounds reflectography as well as additional examinations with survives beneath the grey paint. One of the purposes a microscope. Further extensive investigation was made of this article is to present the material evidence from of the original back-grounds in 2005 in conjunction technical examination to attempt to reconstruct as far with some small cleaning tests.7 This article amalgamates as possible the sequence of changes that has occurred what has been learned from the earlier campaigns, and and to describe what can be deduced about the original presents further work on the existing samples together appearance of the backgrounds. The different painting with analysis with the more sophisticated techniques techniques used for the two angels are also of considerable now available. These were interpreted in conjunction interest, since they reinforce stylistic considerations with new infrared reflectograms and close study of the which indicate that they are by different painters (neither surface of the paintings with a stereomicroscope.8 of course Leonardo himself, but both seeking in some measure to imitate his style of painting). These technical variations are particularly clear in the different modes of underdrawing and manners of fl esh painting.

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FIG. 1 Associate of Leonardo da Vinci (Francesco Napoletano ?), FIG. 2 Ambrogio de Predis, An Angel in Red with a Lute (NG 1662), An Angel in Green with a Vielle (NG 1661), about 1490–9. Oil on about 1495–9. Oil on poplar panel. poplar panel.

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Historical origins of the paintings who made his last will and testament in December 1490, since he is not mentioned. If The Virgin of the Rocks now The original contract for the gilding and painting of the in Paris was indeed sold, an explanation is provided of altarpiece by Leonardo da Vinci and the brothers the need for a substitute picture by Leonardo. It is often Ambrogio and Evangelista de Predis is dated 25 April assumed that the Angel panels were left over from this 1483. The altarpiece had already been carved by the first phase of work, and since it was always clear that leading woodworker Giacomo del Maino, work that was they are by different hands, it was reasonable to attribute commissioned in 1480 for the newly built and indepen- them to Ambrogio and Evangelista de Predis. dent chapel of the Confraternity of the Immaculate It is immediately evident, however, that the panels Conception, adjacent to the church of San Francesco now in the National Gallery do not represent pairs of Grande. One part of the 1483 contract (the lista, in angels as the contract stipulated. The wording in the Italian) describes the ingredients of the work, beginning appeal does not make it clear whether two panels, each with a sculpted figure of the Virgin painted in expensive of which depicted two angels, had been painted or, as colours, now usually agreed to have been at the summit is perhaps more likely, that the artists had departed from of the ensemble, and finishing with the predella and the contract with only one angel being painted on each. other parts at the base of the altarpiece. Three main This would seem to be a possibility, since changes to areas were to be occupied by pictures. These included the Confraternity’s desired iconography were instituted two pairs of musician angels – one duo singing and the by Leonardo himself in The Virgin of the Rocks. In other playing – which were to be painted on two ‘empty’ whatever way the musician angels were disposed across spaces or panels, perhaps already set into the altarpiece.9 the two panels completed by the early 1490s, it is likely These are mentioned several items before the ‘Virgin that they would have taken their stylistic cue from and Child with Angels’, the picture that would be painted Leonardo’s Louvre Virgin of the Rocks. The panels now twice by Leonardo, in which he reduced the number of in the National Gallery are, however, stylistically more angels to one and added the infant Saint John. Hannelore compatible with Leonardo’s second (London) picture Glasser has already suggested sensibly that the lista – than the first, and should therefore be considered to be whose elements otherwise appear curiously random – works of the 1490s, made no earlier than about 1492–3. may describe the altarpiece from top to bottom, although The possibility therefore needs to be considered that a she did not follow the logic of her suggestion to consider first set of Angel panels was also sold off, with substitutes what this might imply about the position of the Angels. then needed.12 The paintings in the National Gallery It can therefore be deduced that the Angel panels were would therefore be those replacements – the first set positioned at a level above that of Leonardo’s painting having long ago disappeared. of The Virgin of the Rocks, which occupied the centre of Ambrogio certainly considered his part of the work the main tier, and not on either side of it as is usually finished by the time of a second financial dispute with supposed. These spaces would have been occupied instead the Confraternity in 1503, so if (as is generally believed) by a stacked series of small-scale reliefs of the Life of he is the author of the Angel in Red then it must have the Virgin, which in fact would have needed to be more been completed by then. The only remaining question, visible than would have been allowed by the place in therefore, is whether the Angel in Green was painted only the upper tiers they are usually granted.10 after Leonardo returned to Milan to ‘finish’ The Virgin The painters had received most of their fee by of the Rocks in 1506–8. This seems circumstantially December 1484, but they seem to have realised they unlikely, but from a stylistic point of view cannot be had underestimated the cost of the work and therefore absolutely ruled out. appealed for further payment. Both the Angel panels and The Virgin of the Rocks seem to have been completed by this time,11 since they were judged to be ready to undergo Attributions an estimate procedure, and the artists claimed they had identified a potential buyer for the ‘quadro de una n[ost]ra An Angel in Red with a Lute (NG 1662) has been consis- dona’– the picture generally presumed to be The Virgin of tently attributed to Ambrogio de Predis in recent years, the Rocks now in the Louvre. This appeal is not dated, but by comparison with signed or documented works, or with must have been written after the death of Evangelista, pictures convincingly attributed to him.13 An Angel in

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Green with a Vielle (NG 1661) is perhaps best catalogued Later history of the paintings as a work by an associate of Leonardo da Vinci and Ambrogio de Predis. If it does indeed belong with the The chapel was demolished in 1576 and the altarpiece second phase of work it cannot be by Evangelista was moved into the main body of the church, requiring (although nothing by him that might provide a point complete disassembly and alterations to the structure.18 of comparison is known to survive). It has also been The carpentry was much changed at this time, with those attributed in recent years both to Marco d’Oggiono and aspects that appeared particularly out of date, such as to Francesco Galli (known as Francesco Napoletano). a canopy over The Virgin of the Rocks and reliefs of the There are some similarities with the technique of Life of the Virgin, being sold. It was probably some time paintings by Marco made after 1500, but this attribution around 1579 that the musician angels were moved to is not entirely satisfactory, especially given the greater the lower tier, to be seen flanking The Virgin of the Rocks understanding of his oeuvre resulting from recent by 1671, although, as we have seen, this was probably research by Antonio Mazzotta.14 More convincing is the not their original position.19 By 1781, however, all three view that the Angel in Green was painted by Francesco painted panels had migrated to the upper tier, now placed Napoletano.15 Doubts about this attribution have been above the statue of the Immacolata. The Virgin of the raised, partly on the grounds that it bears little Rocks was subsequently removed, but in 1798 the Angels resemblance to The Virgin and Child in Zurich widely are mentioned as still in the church, on either side of thought to have been signed by him.16 The signature on the void left by the removal of Leonardo’s painting (‘Altri the Zurich panel, however, reads ‘.FR. / [.]LIA.’, and due quadri rappresentanti angioli dipinti sul legno pure despite the general consensus, it is difficult to reconcile incassati in detta ancona’).20 They were sold to Conte these letters with any way that Francesco might plausibly Giacomo Melzi (some time before his death in 1802) after have signed his works. The painter of this picture which they hung as gallery pictures. There were therefore may, therefore, be another artist. There are, nevertheless, several moments which might have called for alterations similarities with more certain works by Francesco: the to the size of the panels and also their backgrounds. altarpiece of The Virgin and Child with Saints Sebastian and John the Baptist in Zurich and The Virgin and Child in the Brera, Milan – both seemingly of the late 1480s – as well as the signed Saint Sebastian panel from the Saint technical study Nicholas of Tolentino altarpiece in Brescia (Pinacoteca Tosio-Martinengo) of 1495, an ensemble that was mostly painted by Vincenzo Civerchio. The panels It is possible to establish that there was some professional and perhaps personal connection between An Angel in Green with a Vielle Francesco Galli and Ambrogio de Predis. Both could be Overall size 117.2 (left) – 117.0 (right) x 60.6 (top) – found working for the Imperial Mint at Innsbruck in 60.8 (bottom) cm early 1494 (with one Accino da Lecco) and Ambrogio was trusted by the heirs of Galli to act in their interests The panel is poplar21 with vertical grain and consists after Francesco died in Venice in 1501. Galli therefore basically of a wide board with two narrow strips of wood becomes a plausible choice of partner for Ambrogio attached on the left. The main board is 53.2 cm wide after the death of Evangelista. If Francesco Galli is indeed and about 2.8 cm thick.22 The pattern of the wood grain the author of the Angel in Green, it must predate 1501, (visible along the top edge) indicates that the panel is a which is the year he died in Venice. It is likely to belong tangential cut from near the centre of the tree. The back to the second half of the 1490s, since the angle of the shows marks resulting from finishing using a hand tool head, the fall of the hair and the facial type all depend, with a curved blade, such as an adze or curved chisel, as Brown has realised,17 on the figure of Saint John the and in places shows the uneven finish caused by splitting Evangelist in Leonardo’s Last Supper. the wood, indicating that the panel is certainly still its original thickness. The two narrow strips of wood, which have vertical grain, are both attached with large hand-made, square-

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section nails (visible in the X-ray images); the inner strip is 4.4 cm wide, to which is attached a second piece of wood23 3 cm wide. The backs of these strips have also been finished using hand tools but, while the tooling on the main board is predominantly diagonal, that on the strips is in a vertical direction and nowhere do the diagonal strokes continue onto the additions. This might suggest that, although old, neither was part of the initial construction. However, while the outer piece of wood was probably added later (see argument below) examination of the ground and paint layers on the inner addition shows that the same priming has been used as on the main part of the panel. This piece of added wood, which FIG. 3 NG 1662, Angel in Red, detail from the reverse of the panel makes the panel up to the same size as that for the Angel showing the tooling. in Red, must therefore be part of the original construction. The nails attaching the outer piece of wood on the left have been cut, implying that some wood has been about 2.8 cm thick but narrowing to only 1.8 cm in an trimmed from this edge. At the right edge is stuck a very area to the left of the middle near the bottom edge. thin sliver of wood (about 2 mm wide at the bottom) The pattern of the wood grain (visible along the bottom which tapers until it disappears at about 33 cm above edge) and the way the back has been finished (FIG. 3) the bottom edge. Its status is not clear, but its presence are the same as those described for the Angel in Green. suggests that at some time more wood was attached to The narrow strip at the left edge is 3.4 cm wide at this edge, all but a trace of which has subsequently been the bottom, tapering to 2.2 cm wide at the top. It is removed. This theory is confirmed by the presence of attached and finished in a similar way to the additions several square-section nail holes in this edge. on the Angel in Green, and the nails that were used have Both vertical edges have therefore been altered more been cut, leaving remnants embedded in the wood. The than once; more wood has been added, using similar remains of similar nails can also be seen embedded in carpentry techniques to the original panel – making the right edge of the panel, suggesting that more wood the whole construction wider – and the extra wood has was once attached here too. Both edges have therefore subsequently been totally or partially removed. A further been altered, but both have been finished using a hand change from the original state is indicated by the fact tool, suggesting that the alterations were made some that the top and bottom edges show signs of having been time ago. As with the Angel in Green the top and bottom sawn. This is not how the original panel would have edges show signs of having been sawn. been finished, implying that they have been cut later and, since the top of the arch of the grey niche is missing, the cutting must have occurred after the non-original Preparatory layers backgrounds had been painted. Both panels have been prepared for painting with layers of gesso.25 On both, the gesso is continuous to the top, An Angel in Red with a Lute bottom and right edges but the non-original outer pieces Overall size 118.0 (left) – 118.6 (right) x 60.9 (top) – of added wood on the left have not been prepared for 61.0 (bottom) cm painting; the wood is left exposed. The grey paint of the niches is continuous to the top, bottom and right edges Like the Angel in Green, the panel on which the Angel in on both panels and up to the unpainted wood at the Red is painted is poplar,24 with vertical grain. It consists left, resulting in current painted widths of approximately of a broad piece of wood with a narrow strip attached 58.0 cm for the Angel in Green and approximately 58.7 cm on the left. The main panel is not strictly rectangular, at the top and 58.0 cm at the bottom for the Angel in Red.26 measuring 57.6 cm wide at the bottom but 58.7 cm at Over the gesso on both panels is a pale orange-pink the top. The thickness of the panel varies, being generally oil priming consisting mainly of lead white, with small

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amounts of red lead, lead-tin yellow and an even smaller to the lower layer on the Angel in Green, appearing more quantity of verdigris (FIG. 4).27 Verdigris seems to be a cream-coloured and less pink than the upper layer on relatively unusual ingredient in a priming, although the Angel in Green, as can be seen through cracks in the another example of a very similar mixture to that on the surface paint. Angel panels has been found on the Portrait of a Woman in Profile (NG 5752) attributed to Ambrogio de Predis (see pp. 92–4 of this Bulletin) and on Boltraffio’s Virgin and Underdrawing Child now in the Museum of Fine Arts in Budapest.28 It is also mentioned as one possible component of primings Infrared reflectography (IRR) shows underdrawing and by Armenini in his treatise of 1586 and by Leonardo in changes made during the painting of the two pictures but, his notes for a treatise on painting.29 Many large lead soap since the grey paint of the niche is not well penetrated, agglomerates have formed in the priming on the Angel interpretation of the reflectograms remains difficult. panels due to reaction of the pigments with the binding medium. These protrude through the paint layers above, especially where the paint is thin.30 Angel in Green There is, however, some difference in the preparation between the two panels in that the priming for the Angel Infrared reflectography reveals underdrawing for the in Green has been applied in two layers.31 The lower layer angel which is simple and linear (FIG. 5).The drawing is in is slightly more opaque and less strongly coloured, with a liquid medium and is of the type which can be associated the red lead pigment well dispersed, while the second layer withthereinforcingof adesignwhichhasbeentransferred is slightly more yellow in hue and the red lead seems to mechanically (for example by the use of a pricked cartoon, have formed larger agglomerates of pigment (see FIGS 25 or a tracing). In addition to outlines there is hatching for and 28). The greater translucency of the upper layer shadows, made with careful parallel strokes in the face may be due to more extensive lead soap formation, (see FIG. 13), but freer and more scribbled in the drapery. perhaps as a result of higher concentrations of lead-tin The drawing is followed closely; there are few changes yellow and red lead. The single priming layer on the Angel apart from the sound holes in the vielle, which were in Red (see FIGS 31 and 32) seems to be most comparable first drawn higher. During the course of its execution, the angel’s face was made slightly narrower by painting over part of the cheek.

Angel in Red

In addition to drawing for the figure visible with IRR (FIG. 6) there is a network of straight lines which forms a grid. These lines are only visible in parts of the angel, but enough of each is clearly visible to make it possible to generate the whole grid (see diagram, FIG. 7). Parts of six horizontal lines can be seen and these are spaced about 16.5 cm apart (shown as white lines in the diagram). Parts of three vertical lines are also visible. At first sight these do not so clearly make a regular grid, since two around the middle of the painting are too close FIG. 4 NG 1662, Angel in Red, unmounted sample from the grey paint of the niche, to the left of the tip of the angel’s proper left together. However, the distance between the two outer wing. The grey surface paint has cleaved from the layers below visible lines is again 16.5 cm (the white verticals in the it, revealing the pinkish-brown paint of the original background (lead white, black and vermilion). In part of the sample the priming diagram). A grid of 16.5 cm squares can therefore be is exposed and can be seen to consist of lead white, red lead, completed (see the yellow lines in the diagram). The extra lead-tin yellow and some large particles of verdigris. In the centre of the sample is a large lead soap pustule, which originates from vertical line that does not fit this grid was drawn in what the priming but has broken through the upper layers of paint. would have been the exact centre of the original panel

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FIG. 5 NG 1661, Angel in Green, infrared reflectogram. FIG. 6 NG 1662, Angel in Red, infrared reflectogram.

before the extra wood was added (the red line in the liquid medium, the slightly broken appearance of some diagram). At the top and bottom of the panel (both of consistent with brush drawing skipping over the texture which we know to have been cut) the rows of 16.5 cm of a swiftly brushed priming layer. It looks freehand and squares are not complete; the bottom would require takes the form of many short strokes, feeling for contours another 4.5 cm of panel to complete the squares, while and trying small changes. This description applies at the top more is missing and the panel would need generally to all the underdrawing on this panel, although another 11 cm. This would give a panel 132 cm tall and the drawing for the head shows fewer changes and seems about 58.5 cm wide (red dotted line in diagram).32 This to have been more carefully followed in the paint (perhaps seems a reasonable assumption since it gives more space suggesting that a separate detailed drawing for this part to complete the painted niches, which, although not once existed). The squaring of the panel suggests that original, must have had panel to be painted on. the overall design of the figure was copied freehand from In the reflectograms the underdrawing for the angel a squared drawing, a method which enabled designs to is most easily visible in its right hand, drawn on the first be enlarged while still being copied accurately. position of the lute (FIG. 8).The lines of the underdrawing In the underdrawing, the figure holds the lute in are quite narrow and sketchy looking but clearly in a a position to the right of and lower than where it now

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FIG. 7 Diagram to is. The right hand is angled more diagonally downwards, show the grid on with the fingers straighter, and with the sleeve of the the Angel in Red. right arm over the front of the lute. Both IRR and X-ray images show that painting had begun with the angel holding the lute in the first position before the change was made. There is also some underdrawing for a lute closer to its final position, and for the sleeve and hand as they were finally painted, so this was clearly a problem the artist was working out as he went along. Another change, perhaps associated with the shift of the lute, is that the angel’s right wing seems originally to have been lower – a wing-shaped area, appearing lighter in the reflectogram, reaches up to the level of the angel’s nose, suggesting that the darker background paint was blocked in around a wing in this earlier position. Paint for the background has also been laid in on the left, some of it quite dark, which is why the fingers of the angel’s right hand (as it appears now) seem so strongly shadowed – they are painted over dark background

FIG. 8 Detail from FIG. 6 showing underdrawing for the angel’s right hand on the lute in its first position.

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paint up to the edge of the lute in its first position. In the drapery the contours of the folds are under- drawn but there is no hatching. In addition to those necessary to accommodate the change in the position of the lute, some changes were made to the drapery during painting, the most obvious on the right near the bottom.

Painting technique of the figures

The medium used for the original paint is walnut oil.33 Both panels show areas where the paint has suffered from drying problems, causing disfiguring cracking or FIG. 9 NG 1661, Angel in Green, photomicrograph of wrinkling. These occur in many of the darkest areas the angel’s nose. such as the hair and dark parts of the wings, in the red draperies on both angels, and in areas on the Angel in Red where changes have been made during painting, registers in X-ray images; even the highlights in the such as the repositioning of the lute. flesh are barely visible. Not surprisingly, given the Similar defects are seen in many works by Leonardo high proportion of black in the paint, the highlights in himself, including the London Virgin of the Rocks, and also the face appear grey in IRR, with the shadows being in works by other artists of his circle.34 far darker (FIGS 12, 13 and 14). At the top of the angel’s forehead a small area of the pinkish priming has been left exposed which contrasts strongly in IRR with the Angel in Green adjacent flesh paint (although this is a light area of the face) demonstrating the highly infrared-absorbing The greyish hue of the flesh and the strong contrasts nature of the paint. In some places the lighter strokes between light and shade are among the most distinctive of flesh paint have been spread over adjacent colours, characteristics of this painting. From the surface the leaving a fingerprint-like texture in the paint,36 suggesting flesh paint can be seen to contain an unusually high that the artist was manipulating the paint with his proportion of black – in the form of large particles with hands so as to soften the contours (FIG. 10). the splintery shape characteristic of charcoal – even in The green drapery of the angel is painted with thickly the highlights. Although an essentially opaque paint applied verdigris mixed with a little lead white and mixture of lead white with red lake, vermilion and the lead-tin yellow (FIG. 11). The strongest highlights are charcoal black already mentioned was used for the more opaque than the surrounding green paint as they highlights and mid tones, it is rather thinly applied so that contain far more lead-tin yellow. There is a dark modelled it has a greyish opalescence. The areas of deepest shadow underpaint in warm greenish grey containing a high seem to contain very little white, and in the one sample proportion of black mixed with some yellow earth and of flesh paint that exists (from the shadow of the angel’s only a little lead white. It is this that is responsible for right hand) the paint can be seen to consist mainly of the modelled appearance of the drapery in IRR. The charcoal black and red lake. The particles of the red lake underpaint is exposed in the area between the fingers of pigment are large and have a distinctive tabular shape, as the hand holding the bow, where little if any green has well as an orange fluorescence in ultraviolet light that been applied to provide the deep shadows.37 suggests that it contains madder dyestuff.35 The lower parts of the sleeves of the angel are dark The modelling of the flesh is achieved by blending red. The one cross-section from this area shows that here different mixtures of the pigments (lead white, red lake, too there is a very dark underpaint, in this case consisting vermilion and black) into what becomes a single thin almost entirely of black pigment. The red paint on top smooth layer of paint, with only a few touches super- contains what seems to be the same madder red lake seen imposed, such as the highlights and a very red stroke on in the flesh, some powdered colourless soda-lime glass, the nose (FIG. 9). As a result, the original paint hardly a little black (accounting for the slightly dull red tone)

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FIG. 12 NG 1661, Angel in Green, detail showing the head of the angel.

FIG. 10 NG 1661, Angel in Green, photomicrograph of the edge of the angel’s front foot showing a fingerprint in the paint of the highlight.

FIG. 13 NG 1661, Angel in Green, detail from infrared reflectogram (FIG. 5) showing the head of the angel.

FIG. 11 NG 1661, Angel in Green, paint cross-section from an area of shadow in the upper green part of the angel’s upper proper right sleeve. One or two thick layers of verdigris (mixed with a little lead white and lead-tin yellow) lie on top of a warm grey underpaint (black, yellow earth and lead white) which is modelled across the drapery. The two layers of priming can be seen on top of the gesso ground, the upper one being slightly more translucent. Overall the priming has a pinkish hue, but the tinting pigments are quite sparsely dispersed and here only lead-tin yellow can be seen mixed with lead white. Beneath is the gesso ground.

FIG. 14 NG 1661, Angel in Green, detail from an X-radiograph showing the head of the angel.

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FIG. 15 NG 1662, Angel in Red, detail showing the head of the FIG. 18 NG 1662, Angel in Red, photomicrograph of the angel’s angel. nose.

and a very little lead white (FIGS 19 and 20). This layer structure and the poorly drying, thick, medium-rich paint probably accounts for the bad drying cracks in this area.38 Some details, such as the white puff of shirt issuing from the red sleeve at the angel’s right wrist, and the bow on the strings of the vielle, were painted over the paint of the sleeve and the vielle respectively.

Angel in Red

The flesh paint is quite different from that in the Angel in Green; the whole tonality is warmer and pinker. There seems to be a modelled layer providing a basic pink skin FIG. 16 NG 1662, Angel in Red, detail from infrared reflectogram (FIG. 6) showing the head of the angel. tone, and, unlike the flesh of the Angel in Green, there is only a little black mixed into the paint in shadows such as that at the side of the nose, and the darker areas are more brown than grey (FIG. 15).39 A sample from the brown shadow of the foot of the angel confirms that the paint is a mixture of lead white, vermilion, red lake and a little black.40 Over the base tone there is further modelling in brown for the shadows and a much paler pink which is thickest in the highlights (for example those on the chin, the upper lip, the tip of the nose and the eyelids). These thick unblended highlights, containing a high proportion of lead white, register strongly in the X-radiographs, resulting in an image with greater contrast in the areas of flesh than in the equivalent X-ray image of the Angel in Green (FIGS 16, 17 and 18). The paint of the red dress has suffered badly from drying problems which have caused it to break into small FIG. 17 NG 1662, Angel in Red, detail from an X-radiograph showing the head of the angel. islands, showing the orange-pink colour of the priming

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grams. From the reflectography it would seem that at least the underpaint for the dress was laid in before it was decided to change the position of the lute, the darker area carefully skirting the first position. Some highlights were included (these show better in X-ray images), but it is not clear how finished the dress was before this major change was made. FIG. 19 NG 1661, Angel in Green, paint cross-section from lower red part of the angel’s proper right sleeve. A thick cracked layer of red lake mixed with coloured powdered glass can be seen over the dark modelled underpaint, which here consists almost entirely of charcoal black. Two priming layers, with some transparent lead Backgrounds soap agglomerates visible in the upper layer, lie on the gesso ground.

The most substantial alteration to the original appearance of both the musician angel panels wasto the backgrounds, which are covered and concealed by the grey niches in which the angels now stand; these were themselves subsequently changed when the tops of the panels were cut, removing the apexes of the arches. As Plesters has already noted, the grey paint we see today, thick and coarsely applied with rather crude brushstrokes, FIG. 20 NG 1661, Angel in Green, paint cross-section illustrated in is certainly not original.42 In places this paint overlaps FIG. 19 photographed under ultraviolet light. The red lake particles the original contours of the angels, or leaves original have a distinctive orange fluorescence which suggests they contain madder dyestuff. The jagged glass particles are also visible, background exposed, altering their basic outlines (FIG. including one that is particularly large at the left of the sample. 22). Unfortunately neither the pigments nor the binding medium used in the grey paint have any characteristics which allow for exact dating,43 but cross-sections show that it is applied over a layer of varnish which has had time to crack and to accumulate a significant quantity of dirt on its surface (FIG. 23). This leads to the question of the original appearance of the backgrounds. Unfortunately the X-ray images are dominated by the pattern of brushstrokes from the later grey (lead white-containing) paint, while IRR gives only a limited idea as to what lies beneath, due to the thickness

FIG. 21 NG 1662, Angel in Red, paint cross-section from the angel’s red drapery showing the gesso ground and the orange-pink priming, followed by the opaque brick red underpaint consisting of black, red earth and vermilion. The upper red layers contain varying proportions of red lake and vermilion. The wrinkling that can be seen at the paint surface is also evident in the cross-section in the contours of the layers.

through the cracks.41 Cross-sections show that there is a rather dull red modelled underpaint containing red earth, black and a little vermilion (FIG. 21). Over this layer is a brighter red paint based on vermilion and red lake, sometimes with a further red lake glaze. The

underpaint contains pigments which absorb infrared FIG. 22 NG 1661, Angel in Green, photomicrograph of the and which therefore appear dark in infrared reflecto- non-original grey niche paint overlapping green drapery.

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FIG. 23 NG 1661, Angel in Green, paint cross-section from the grey niche just to the right of the angel’s head, showing the non-original grey paint running into cracks in a yellowed and dirty varnish layer below it. Beneath the varnish is the paint of the original background, which at this point is dark greenish grey (black and a little yellow earth and lead white).

FIG. 24 NG 1661, Angel in Green, photomicrograph of background near the top of the angel’s left wing showing blue paint under of the paint and the high proportion of carbon black. non-original grey niche paint. Despite these hurdles, some features visible in these images give clues which, when combined with careful examination of the surface with a stereobinocular microscope (the lower paint layers could be seen through cracks in the surface paint) and information from paint cross-sections, permit some conclusions to be reached.

Angel in Green

FIG. 25 NG 1661, Angel in Green, paint cross-section from the grey In the X-ray images incised lines can be seen running niche just above the area illustrated in FIG. 27. Two layers of varnish vertically just inside the incisions marking the inner with dirt between them are visible here below the pale grey paint edges of the front of the grey niche. At the top the of the niche. The greyish blue paint of what appears to be a distant landscape contains ultramarine and a little lead white and black. incisions curve inwards to form the beginning of an arch, Beneath are two greenish-yellow layers; a thin darker duller paint suggesting a niche, but one with a steeper profile than consisting of yellow earth and black and, immediately on top of the priming, a brighter yellower layer consisting of lead-tin yellow, that used for the overpainted grey niche. The left vertical yellow earth and lead white. The two layers of the priming on the passes through the angel’s right sleeve, while that on gesso are evident, with some lead-tin yellow and red lead mixed the right is continuous through the angel’s wing, so if with lead white and some translucent lead soap agglomerates. these do represent plans for a niche, the angel must have been standing in front of it. Even though the grey paint of the later niche is not opening, bright blue paint suggestive of a sky can be easily penetrated by infrared, some differences in the seen (FIG. 24). Further down, in the area below the pattern of light and shade can be seen which seem to give wing which still appears light in the infrared image, the further clues to the background’s original scheme (see original background (seen again through the cracks) FIG. 5). Above the angel’s wing on the right of the panel becomes a more greyish blue, perhaps suggesting distant there is an area with a curved boundary which appears hills, whereas near the bottom of the niche there is a lighter (like an arched opening seen at an oblique angle). relatively strong green colour, as might be expected in Much further down, below the area where the green the foreground of a landscape. Paint samples confirmed drapery billows out to the right, a straight vertical these observations, identifying the bright blue paint as a boundary can be seen between a dark zone on the left mixture of ultramarine and lead white, while the greyer and a lighter area on the right, which could be the paint of what might be the distant landscape contains bottom part of this opening. Looking through cracks ultramarine with only a small amount of lead white and a in the grey surface paint above the angel’s left wing, in little black (FIG. 25). The strong green paint lower down what would be the upper part of this possible arched consists of verdigris mixed with lead-tin yellow, yellow

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FIG. 26 NG 1661, Angel in Green, paint cross-section from the grey FIG. 28 NG 1661, Angel in Green, paint cross-section from a dark niche, towards the bottom right of the painting. The grey paint has grey area of the niche, towards the bottom left of the painting (but cleaved from the sample. Only the paint of the original background within the incised line of the arch of the original background). is present, which at this point is a strong green colour from what The dark grey paint, on top of a varnish, contains distinctive large appears to be landscape (verdigris, lead-tin yellow, yellow earth and particles of white and black pigment that give the paint a granular a little lead white and ultramarine). texture. The paint of the original background is mustard brown at this point, consisting mainly of yellow earth with a little black. A lead soap pustule is pushing up this paint at the left of the sample. earth, lead white and a small amount of ultramarine (FIG. 26). After the campaign of examination carried out between 2003 and 2005, a cleaning test was made very top of the panel, above the angel’s head, the original to ascertain whether it might be possible to remove the background paint appears a rich chestnut brown, while grey paint safely, exposing a small part of the original further down to the left of the angel there seems to be background just above where the green drapery projects a dark greenish brown. A cross-section from this area to the right at about knee level, where there is greyish shows that there is a thin black layer over a rather more blue paint which might be distant landscape (FIG. 27).44 orange-brown paint composed of yellow and red earth Thisgivesaclearerideaof thepossibleoriginalappearance with some black. Further down on the left and nearer in this area of the painting. the edge of the niche, the original paint appears to be Further to the left, between the angel’s left wing and a similar but brighter orange brown which can be seen its head, black paint is visible through cracks in the grey from samples to consist of the same mixture of earths but paint, which in a cross-section from this area can be seen with less black pigment (FIG. 28). to have been applied over a dark greenish-brown paint Under the angel’s feet is a band which appears dark consisting of black mixed with some yellow earth. At the in the reflectograms, with very straight edges as though ruled; it extends diagonally from the curved bottom edge of the niche on our left towards the bottom of the panel, passing under the front foot (as if the angel was standing at the edge of a step set diagonally to the picture plane). This diagonal band can just be made out in the X-ray image and would appear to have incised edges. A cross-section from this area confirms that there is black paint in the area of this band, which in cross- section lies over a more brownish paint of yellow earth and black with a little lead-tin yellow and lead white. To the right of the angel’s feet at the bottom of the panel the original background paint is a darker greenish brown (black and yellow earth) similar to that in the darkest areas behind the angel. These observations, taken together, suggest that the first background for the Angel in Green placed the angel on a step in front of an arch, with a dark brown backdrop behind it which varied in tone (perhaps a curved niche), but that behind its wing on the viewer’s right a view opened out to a landscape with sky, perhaps FIG. 27 NG 1661, Angel in Green, detail from a photograph taken distant hills and a greenish foreground (see FIG. 34). after an area of original background paint below the angel’s left wing had been uncovered during tests in 2005, showing the original paint of a distant landscape.

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Angel in Red

It is much more difficult to establish what is below the grey niche behind the Angel in Red. One unexpected finding, however, is that this angel had a halo, a simple curved line of gold leaf, now completely covered with the grey paint.45 As with the Angel in Green, in X-ray images vertical incisions are visible inside those made for the grey niche and finishing with arcs as though an arch or niche was planned for the original background. The incised vertical line on the left cuts across the angel’s right hand, although before the lute was moved, the angel would just have fitted between the incisions. Also visible in the X-ray images are many scratches (or perhaps incisions) which do not obviously relate to the original composition and are difficult to interpret. Most interesting are a series of curved lines at shoulder level which cross the wings and some of the hair, although not the neck. These would seem to consist of a mixture of incisions and brush strokes (they also show in IRR) and they line up with the springing of the incised arch. What these are, and at what stage they were made, is impossible to determine for certain, but they were probably made before the angel’s wing was FIG. 30 NG 1662, Angel in Red, detail showing exposed background paint near the angel’s right hand. painted and might suggest that the original background planned for this angel was a curved niche. Exposed at the surface around the angel’s foot (FIG. the grey niche, outside the incised lines seen in the X-ray 29) and below the grey at the bottom of the panel (both image that seem to relate to the original background, the light grey of the floor of the niche and the dark grey at the colour is similar but stronger, made with the same the edge) there is paint which has a salmon pink colour mixture of pigments but with some vermilion, red lead (not a single flat area but varying in intensity as though and a little black in addition.46 This colour is most easily there is some modelling). The pigments identified in this seen where grey niche paint has not been brought mixture in a sample from this area were red earth and a right up to the red drapery around the sleeve of the small amount of lead white. Under the flat front part of angel, leaving visible some original background paint which now reads as though it is part of the red drapery (FIG. 30). Within the curved part of the niche on the left the original background paint seems to be very dark brown. On the right this brown paint seems to be lighter in tone. Cross-sections from various areas con- firm these observations, finding brownish and pinkish layers beneath the grey, sometimes two different colours over one another, made from mixtures of black, vermilion, red earth, lead white and sometimes a little lead-tin yellow (FIGS 31 and 32).47 Taken together, these observations suggest that the original background against which the angel was placed was also a niche, much the same as the grey one in shape but narrower and a different colour (see FIG. 33).

FIG. 29 NG 1662, Angel in Red, photomicrograph of paint below the angel’s back foot showing original background colour.

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of wood. The panels retain their original thicknesses; their reverses, which have been roughly finished using a hand tool, have never been decorated and would never have been intended to be visible. The idea that has been proposed in the past, that the two Angels were once front and back of a single panel, or that one was the front and the other the back of different movable double-sided wings, can therefore be firmly rejected. The paintings are confirmed as the work of two FIG. 31 NG 1662, Angel in Red, paint cross-section from the light artists – in addition to their different styles, they have grey of the niche to the right of the angel’s feet showing orange paint similar to that visible in FIG. 29 directly on the priming different types of underdrawing and painting techniques (yellow and red earth with a little black and lead white). Between – but they also have aspects in common. It has long this original background paint and the light grey of the niche are two layers of varnish between which is a layer of dirt. been recognised that the two angels are the same size and that their poses, in particular the swirling draperies and the feet, are very similar. These observations have led to suggestions that one was copied from the other: usually, since the style of the Angel in Green is more like Leonardo’s and therefore might have been painted later, the Angel in Green is assumed to have been copied from the Angel in Red.48 The results of infrared examination might seem to confirm this theory, since the underdrawing of the Angel in Red has been executed freehand, with the help of a grid, while that for the Angel in Green is based on mechanical FIG. 32 NG 1662, Angel in Red, paint cross-section from a dark grey area of the niche on the left and just below the angel’s lute. transfer from a cartoon (or cartoons). However, although The original background paint, on top of the pale pinkish priming, the distinctive patterns of some of the main folds do consists here of two pinkish brown layers (vermilion, black, lead occur in both pictures, there are nonetheless significant white and a little lead-tin yellow). The first is similar in tone to that visible in the sample in FIG. 4 but the second is much darker, differences between the draperies. By overlaying images containing hardly any lead white. of both, it becomes evident that the correlation is not as close as would be expected if a tracing made from the finished draperies of the Angel in Red had in fact Conclusions been used for the Angel in Green’s costume. Repaints on the red drapery and the grey niches have, as we have The documentary evidence on these two panels and seen, substantially changed the surface appearance of their companions gives rise to a number of questions the pictures, so a second overlay was made comparing relating to their history after the altarpiece was first the infrared reflectogram of the Angel in Red with that installed. Some of these are answered, to some extent, by of the Angel in Green. This confirmed the differences in the technical examinations described above. It is clear the draperies and produced another – unexpected and that the significant alterations made to both panels significant – finding. When the images are overlaid so that during the five centuries since they were painted were the feet of the angels are lined up as well as the drapery, several and probably took place at different times. It is the right hand of the Angel in Green (holding the bow) now possible to give some idea of what the pictures was found to be in exactly the same position as the right might have looked like before they were overpainted and hand underdrawn for the Angel in Red in its first position, cut down. before the lute was moved. The right shoulders and the The original poplar panels on which the Angels are angle at which the arm descends also correspond closely. painted are both about 58 cm wide; that for the Angel We can therefore conclude that the Angel in Green in Red was fashioned from a single piece of wood, while was not copied from the finished Angel in Red. Nonetheless that for the Angel in Green from a slightly smaller board there is clearly a relationship between the two. Of the made up to the same width by attaching a narrow strip several possible scenarios, the one that seems best to

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FIG. 33 NG 1662, Angel in Red, diagram to show, in simplified form, FIG. 34 NG 1661, Angel in Green, diagram to show, in simplified what is known about the structure and colours of the original form, what is known about the structure and colours of the background. original background.

accommodate all the new facts is that the two different Stylistically, we are forced to conclude that these painters were supplied with the same design for a standing Angels are very unlikely to date from the time of the first angel and then allowed to adapt it and work it up to full commission. This view is now supported by aspects of size independently so that the angels would have different their painting technique which they share with other heads and instruments. They each used a different Milanese paintings of the 1490s.49 method, one choosing to copy the design using a grid and We therefore need to consider how the Angels now to make the necessary modifications on the panel, the in London came to replace whatever pictures were other making a cartoon. This relationship between the installed before the artists made their first unsuccessful two paintings requires that they were painted at much appeal to the confraternity. The technical examinations the same time, and certainly excludes proposals made in discussed above revealed no signs that there was ever an the past that they differ widely in their dates of execution. earlier painting on either panel. The musician angels

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must therefore have been painted afresh in a style that After the varnish applied over the paint had had better matches the second (London) version of The Virgin time to crack, and a layer of dirt had formed over it, the of the Rocks. Although they appear from the lista to have backgrounds of both Angels were overpainted with the been intrinsic to the original structure, it is possible that grey niches seen today, making them look more similar the first angel panels were extracted and sold when than they would have originally. Some time after this Leonardo’s Louvre Virgin of the Rocks found a buyer. The intervention, the top and bottom edges of both panels whereabouts of the first set of Angels remains a mystery were cut with a saw, making it impossible to gauge their that is unlikely ever to be solved. original height. It seems likely, however, that they would From the clues available it is possible to make some have been tall enough for the non-original grey niches tentative suggestions as to the appearance of the original to be complete at the top. Based on the grid found on backgrounds of the National Gallery panels (FIGS 33 and the Angel in Red, it is possible that the panel might have 34).50 On both there are incised lines marking the inner been 132 cm high (that is, eight rows of squares each border of an arch which is narrower and more pointed 16.5 cm high). than the arches of the grey niches (shown as white lines None of the results from the technical examination in the diagrams). In both cases the angels slightly overlap solve the question of where the two angel panels were these incised lines, suggesting that they were originally originally located in the altarpiece, but if they were in an depicted standing in front of arch-topped structures. All upper tier it might explain how the two artists escaped the colours seen through cracks or in paint samples censure for these rather dissimilar backgrounds. The from the background of the Angel in Red are variations documentary evidence indicates that they were later of pink, orange or brown, ranging from quite bright brought down to the main tier, flanking The Virgin of the colours, similar to the strongest flesh tones in the angel, Rocks; in this position the discrepancy in their ill-matched to dark browns. The distribution of the various colours backgrounds would have become more unsettling, tends to match the variations in light and dark of the suggesting that it was probably then that the grey niches grey niche, suggesting that the original background was were added. The changes in carpentry described above also a niche, similarly lit but made from red-brown could also have happened at this time, since it would stone. The results from the Angel in Green remain harder probably have been necessary to make new frames or to understand. Behind and to the left of the angel there fit the panels into different spaces in the altarpiece, but seems to have been deep shadow, but to the right was the subsequent sawing of their tops is more likely to an opening that probably had an arched top (not incised) have taken place when the panels were moved back to where brighter colours were found: blues, blue-greens an upper tier. and bright greens, which can be interpreted as a view Many questions remain to be considered. In of distant landscape. It has not been possible, however, particular, the two musician angels in their grey niches to determine what colour the flat part of the niche (the do not make a very good pair, and what has been found incised structure) was painted, as so little of the original about the original backgrounds suggests that they background survives beneath the grey paint in this were even less well matched when first painted. How area.51 The infrared image suggests that the angel may they worked, together and within the whole altarpiece, be standing on an angled step, so the niche may also therefore continues to be unresolved and is still an have been at an angle. open subject for further discussion. Future considerations Some time after they were first installed in the of these issues can now, however, be informed by a altarpiece more wood was glued and nailed to both the more complete understanding of the physical evidence lateral edges of each panel. Where they are still extant offered by the paintings themselves. (at the left) these additions are unpainted. Why it should have become necessary to add extra unpainted wood to the edges of the panels is not clear, but it is known that Acknowledgements the Angel panels were moved at least once, probably twice, to different positions within the altarpiece and it seems This article draws on work done by many current and likelythatoneof thesemovesdemandedtheirenlargement former colleagues at the National Gallery going back to to fit a different-sized frame, or to allow a new frame to the 1940s. Much of this is already published, but we be attached.52 are particularly grateful to Ashok Roy and Helen Howard

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for sharing their unpublished work on the samples ancona de figure de relevo misa tuta de oro fino et uno quadro de una n[ost]ra dona depinta a olio et dui quadri cum dui angeli taken in 2003–5 as well as some re-examination of the grandi depinti similiter a olio …”, see Beltrami 1919 (cited in note 2). older samples that took place at that time. We would 12 This could perhaps have presented difficulties if the panels were also like to thank David Peggie for carrying out some indeed part of the altarpiece structure as the lista implies (see note 9), although complex altarpieces at this time were usually further medium analysis supplementary to that already made in such a way that they could be dismantled. If these panels published. remained in situ, this implies that they must have been completely repainted to match Leonardo’s later style more closely. In some measure this is suggested by Cannell although, as we shall see, This article is available for download at: there is no technical evidence to support such an assertion. See Cannell 1984 (cited in note 2), p. 104. http://www.nationalgallery. org.uk.technical-bulletin/ 13 See argument by L. Syson, ‘Leonardo and Leonardism in Sforza billinge_syson_spring2011 Milan’, in S.J. Campbell (ed.), Artists at Court: Image-Making and Identity, 1300–1550, Boston 2004, pp. 106–23, esp. pp. 111–14 (albeit in which the Angel panels are assumed to belong to the first phase of the partners’ work on the altarpiece). Notes 14 Syson 2004 (cited in note 13) tentatively attributed the Angel in Green to Marco d’Oggiono on grounds that no longer seem to him convincing. For Mazzotta see L. Syson et al., Leonardo da Vinci: 1 M. Davies, National Gallery Catalogues. The Earlier Italian Schools, Painter at the Court of Milan, exh. cat., National Gallery, London 2nd edn (rev.),London 1961 (1st edn 1951), p. 270. 2011, pp. 130–33. 2 For a reasonably complete and up-to-date bibliography on 15 This was first proposed by David Alan Brown in 1984 (see ‘A Leonardo’s paintings see F. Zöllner, Leonardo da Vinci, 1452–1519; Leonardesque Madonna in Cleveland’, in M. Natale (ed.), Scritti di The Complete Paintings and Drawings, Cologne 2003, pp. 223–4, storia dell’arte in onore di Federico Zeri, Milan 1984, I, pp. 291–302) 229. For the extensive documentary evidence for the commission, and reiterated by him in D.A. Brown, Leonardo da Vinci. Art and see esp.L Beltrami (ed.), Documenti e memorie riguardanti la vita Devotion in the Madonnas of his Pupils, Milan 2003, pp. 48, 83–4, e le opere di Leonardo da Vinci in ordine cronologico, Milan 1919, note 89. It has been accepted by Janice Shell and MariaTeresa Fiorio pp. 12–20, 73–4, 102–7, 124–7, nos 23–4, 120, 169–70, 195 and (in G. Bora et al., The Legacy of Leonardo, Painters in Lombardy, 1490– 199; G. Sironi, Nuovi documenti riguardanti la “Vergine delle Rocce” 1530, Milan 1998, pp. 126, 209). di Leonardo da Vinci, Florence 1981; W. S. Cannell, ‘Leonardo da 16 Pietro Marani attributes both pictures to Giovanni Antonio Vinci’s Virgin of the Rocks. A Reconsideration of the Documents Boltraffio and Marco d’Oggiono working together (for him the and a New Interpretation’, Gazette des Beaux-Arts, October 1984, principal executors of the London Virgin of the Rocks). See P. C. pp. 99–108. Marani, ‘La Vergine delle Rocce della National Gallery di Londra. 3 I. Rawlins, From the National Gallery Laboratory, London 1940, Maestro e bottega di fronte al modello. “Se tu, pittore, te ingegnerai Plates 31 and 33. di piacer alli primi pittori, tu farai bene la tua pittura…”’, Lettura 4 Davies 1961 (cited in note 1), p. 263. Vinciana, XLII, 13 aprile 2002, Florence and Città di Vinci 2003, 5 For the present study these X-radiographs from 1974 were digitised p. 14, figs 4 and 5. He had previously dated the works in the and assembled into composite images. last decade of the fifteenth century, associating them stylistically 6 An account of the analysis of the samples taken in 1974, as well as with the London picture (although unfortunately placing too much their interpretation by Joyce Plesters, is published in ‘A ppendix C, trust in the authenticity of the niches). See idem., Leonardo: una Some analytical results from the Scientific Department, Nos. 1661 carriera di pittore, Milan 1999, pp. 149–50. His picture captions and 1662, Wings of a Leonardo Altarpiece’, The National Gallery, suggest that at this point Marani credits the attribution of the January 1973–June 1975, London 1975, pp. 67–8. Angel in Green to Francesco Napoletano (albeit a question mark 7 Further samples were taken in 2005 from the grey backgrounds is appended to his name), while he already tentatively and most and examined by Ashok Roy with the assistance of Helen Howard. implausibly ascribes the Angel in Red to Boltraffio. Alessandro 8 In 2003 full infrared reflectogram mosaics were made with the Ballarin also rejects the attribution; see A. Ballarin,‘Riflessioni Hamamatsu Vidicon camera. In March 2005 IRRs were made of sull’esperienza milanese dello Pseudo-Bramantino’, in Problemi di both the paintings using the INOA High Resolution scanner by a Leonardismo Milanese tra Quattro e Cinquecento. Le due conferenze degli team from the Opificio delle Pietre Dure (OPD) and Istituto Nazionale anni ottanta, Padua 2005 (a lecture first delivered in 1987), and di Ottica Applicata (INOA) that included Cecilia Frosinini, Roberto Francesco Frangi remains studiedly noncommittal; see F. Frangi, Bellucci, Luca Pezzati and Pasquale Poggi. We are most grateful ‘Qualche considerazione su un leonardesco eccentrico: Francesco for their assistance. New IRRs were made at higher resolution Napoletano’, in I leonardeschi a Milano: fortuna e collezionismo, Atti with the OSIRIS digital infrared camera in 2011 for this study, del Convegno Internazionale Milano 25–26 settembre 1990, Milan which showed better penetration of the grey backgrounds and 1991, pp. 71–86, p. 74. some other areas of the paintings. The IRRs illustrated here are 17 Brown 2003 (cited in note 15). therefore prepared from these most recent images. 18 Documents cited by Martin Davies (cited in note 1), pp. 261–81, 9 ‘Item li quadri. vodi, sieno. angelli. iiii. per parte differentiati deluno indicate that the first suggestion that the chapel might be moved quadro e l’altro, videlicet. uno quadro che canteno et l’altro che was made in January 1576, the request to move it made on soneno.’ This description implies two panels rather than empty 4 April 1576, and documents record that the change had taken spaces. place by 11 August 1576. For references to documents and 10 This arrangement might have been comparable to that of the guidebooks cited below see also H. Glasser, ‘A rtists’ Contracts of the altarpiece of the Virgin in the church of San Maurizio at Ponte Early Renaissance’, doctoral dissertation, Columbia University, in Valtellina, with the Angels possibly being above the main tier in 1965, New York and London, 1977; Sironi 1981 (cited in note 2); spaces that were equivalent to those occupied by the sculpted M.C. Passoni, ‘Nuovi documenti e una proposta di ricostruzione saints in niches in that altarpiece. Illustrated in L. Keith et al. per l’ancona della Vergine delle Rocce’, Nuovi studi. Rivista di arte ‘Leonardo da Vinci’s Virgin of the Rocks: Treatment, Technique and antica e moderna, 11, 2004–5, pp. 177–97. Display’, in this Bulletin, fig. 33, p.51. 19 Even if the Angel panels now in the National Gallery are 11 “li v[ost]ri fidelissimi s[er]vidori Johanne Ambrosio preda et substitutions for those mentioned in the 1483 contract, they leonardo de vinci florentino se conveneteno cum li scolari de la probably still initially occupied the same position in the altarpiece. c[on]ceptione de sancto fran[cesc]o de M[i]l[an]o, de farli una They were described, however, as lateral panels in the guidebook

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of Agostino Sant’Agostino, L’Immortalità, e Gloria del Pennello, Ouero mentions a priming containing a copper green pigment (verderame) Catalogo delle Pitture Insigni che stanno esposte al publico nella Città di and yellow, although the mixture proposed seems unfeasible in Milano, Milan 1671, p. 42 [reprinted Milan 1980, p. 44, M. Bona practice as it contains a very high proportion of green. The exact Castellotti (ed.)]: ‘Nella Capella della Concettione vi è l’Ancona con meaning of this quote has been much debated since it seems rather la Beata Vergine, e S. Gio. Battista, & à lato due tauolette con due confused and difficult to follow, which might in part be the result of Angioli, che suonano, opere del Celebre Leonardo da Vinci’… This is mistranscription of the original, but the word uerderame seems a repeated in C. Torre, Il ritrato di Milano, Milan 1674, p. 386: ‘Nel clear reference to a copper green. The text is quoted and discussed Frontispizio poi in questa Nave apresi la Cappella dell’Immachiata in note 48 of the article by Jill Dunkerton in this Bulletin. Concezzione di Maria. Ha sull’Altare una Vergine Madre dipinta 30 Red lead, lead white and lead-tin yellow are known to react da Leonardo da Vinci entro vaga Tavola con due Angeli dai lati dello regularly with fatty acids in the oil binding medium to form lead stesso Pittore [our italics] ...’. carboxylates, or lead soaps, which agglomerate and migrate to 20 It is clear from the following description of 1798 that the Angels form large pustules. See C. Higgitt, M. Spring and D. Saunders, were at that time on an upper tier: ‘nella sommità dell’ancona ‘Pigment-medium Interactions in Oil Paint Films containing due pezzi di quadri rappresentanti due angioli’. Davies 1961 (cited Red Lead or Lead-tin Yellow’, National Gallery Technical Bulletin, 24, in note 1), note 87, p. 279. Martin Davies wrongly thought this 2003, pp. 75–95; J.J. Boon, J. van der Weerd, K. Keune, P. Noble late description provided some confirmation of the continuous and J. Wadum, ‘Mechanical and chemical changes in Old Master presence of all three works on the upper tier. Whatever remained paintings: dissolution, metal soap formation and remineralization of the original frame (probably very little by that date) must processes in lead pigmented ground/intermediate paint layers of have long ago disappeared. This was certainly not what could 17th century paintings’, ICOM-CC 13th Triennial Meeting, Rio de be found in the Sormani palace in 1954, as has sometimes Janeiro, London 2002, pp. 401–6; Lead soaps are always found in been claimed. oil paint containing lead-tin yellow, but lead-tin yellow itself

21 Letter from B.J. Rendle, of the Forest Products Research Laboratory, (Pb2SnO4) is less reactive than red lead (Pb3O4) and lead white, in the Gallery archives. and it is probably PbO that is present in the pigment from 22 Although most of the panel is around 2.8 cm in thickness, it is incomplete conversion during preparation that is reacting with not completely uniform. In places it is only around 2.5 cm thick, the oil. Red lead can also contain PbO, depending on how long it while in other areas it is around 3.0 cm thick. was roasted during preparation. See D. Saunders, M. Spring and 23 Also identified as poplar by B.J. Rendle of the Forest Products C. Higgitt, ‘Colour change in red lead-containing paint films’, Research Laboratory (letter in the Gallery archives). ICOM Committee for Conservation, 13th Triennial Meeting, Rio de 24 Letter from B.J. Rendle, of the Forest Products Research Laboratory, Janeiro, London 2002, pp. 455–63. Lead white is often cited as in the Gallery archives. the cause of lead soap agglomerates, but although it does certainly 25 Ca, S and O detected by EDX analysis of cross-sections, indicating react with the oil, it is to a lesser extent than these other lead that the ground layer consists of calcium sulphate. pigments. 26 From examination of X-radiographs there is a suggestion that at the 31 It has not been possible to ascertain the significance of this. The bottom of the Angel in Red the original ground and paint stop before two layers are almost indistinguishable and have been applied the left join, giving a painted width of approximately 57.0 cm, while very quickly one after the other. There is no evidence of one being on the Angel in Green the original paint may not have extended all applied later to cover something already begun. It is more likely the way to the right edge. However as these outer edges are damaged that a second batch of paint for priming was mixed and applied and have more modern overpaint than elsewhere, it is difficult to over the first, perhaps to make it thicker or more even. be sure. X-ray images of the Angel in Green also show a clear pattern 32 The fact that across the width there is not room for four complete of roughly horizontal lines which are more absorbent of X-rays squares might suggest that the original panel was wider, but (and so show lighter); these are probably the result of unevenness the presence of the extra line at the centre of what is present of the in the application of the ground and/or priming. original wood seems to confirm that this was the original width – 27 The tinting pigments are quite dispersed and therefore not all of and that the painter squared up both the painting and the drawing them were seen in every cross-section. Verdigris was seen in samples from which it derives, starting at the left edge. There is no proof that from the background of the Angel in Green and from the red drapery enough wood to complete squares top and bottom was originally and the background of the Angel in Red. It was also visible in a small present, but both edges have definitely been cut, so at least some loss at the bottom edgeof the Angel in Green with a stereomicroscope, is certainly missing. a method of examination that gave a better idea of the distribution 33 Analysis of samples of original paint from the Angel in Red (brown of the tinting pigments. The pigments were identified by EDX from the edge of a wing and red-brown paint under the grey of the analysis on cross-sections. The presence of lead soaps and verdigris niche) by gas chromatography indicated that the binding medium was confirmed by FTIR microscopy in transmission mode in a is walnut oil (see J. Mills and R. White, ‘A nalyses of Paint Media’, diamond compression cell. National Gallery Technical Bulletin, 1, 1977, pp. 57–9). These early 28 Cross-section analysis was carried out by Alan Phenix, Getty results do not provide any indication as to whether the oil was Conservation Institute, while the painting was undergoing heat-bodied. conservation treatment at the J. Paul Getty Museum. We are 34 See L. Keith, ‘In Pursuit of Perfection: Leonardo’s Painting grateful to him for making his report available to us. The priming Technique’ in Syson et al. 2011 (cited in note 14), pp.54–77 and on the Budapest painting contains a higher proportion of red M. Spring et al. ‘Painting in Practice in Milan in the 1490s: The lead, although this is ascribed by Alan Phenix to remineralisation Influence of Leonardo’, in this Bulletin, pp. 78–112 for a discussion following lead soap formation. of drying defects in paintings by Leonardo and the ‘Leonardeschi’. 29 Giovanni Battista Armenini’s discussion of primings states that Although walnut oil is slower drying than linseed oil, a factor that ‘some make it with white lead, massicot and terra di campana; is likely to be at least as important in the development of drying others make it with verdigris, white lead and umber.’ Later he says cracks and wrinkling is the tendency of these artists to use dark ‘But among the tinted primings, one that is held to be good is that underlayers containing very little lead white, therefore applying which tends towards the colour of very light flesh and has a certain faster drying upper layers over those that will dry more slowly. brilliant quality due to the fact that there is more varnish in it than 35 ATR–FTIR imaging on this cross-section indicates that the red lake in the others.’ This is a description that could well apply to the particles contain protein. This is indicative of preparation of the priming on the Angel panels. A few sentences further on he states pigment using dyestuff extracted from wool fibres, with some of the that ‘the priming should be almost entirely of white lead, with one wool being incorporated into the pigment during manufacture. sixth varnish, and a little red that dries at the same rate.’ See This was a common method of manufacture of madder lakes at this E.J. Olszewski (ed. and trans.), Giovanni Battista Armenini on the period. For a discussion of this type of red lake pigment see J. Kirby, True Precepts of the Art of Painting, NewYork 1977, p. 192. Leonardo M. Spring and C. Higgitt, ‘Insight into the Technology of Red Lake

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Pigment Manufacture through Study of the Dyestuff Substrate’, paintings from around 1500 (one altarpiece that was begun by National Gallery Technical Bulletin, 26, 2005, pp. 71–87. We are Maineri and finished by Costa, and one altarpiece by Marco grateful to Satoko Tanimoto, Imperial College London, for carrying Marziale), as well as later in southern Germany (see Spring (2) out this analysis. 2007 (cited in note 38), but it has not yet been identified often 36 For example, in the left hand of the angel the paint of the highlight enough to be able to draw firm conclusions about a pattern of use. along the thumb/palm of hand is spread onto the instrument, the 44 Tests made in the Conservation Department concluded that the highlight on the front foot spreads over the shadow on the back grey paint could not be removed with acceptable control, so no foot and, although it is less clear, something similar can be seen further treatment was pursued and the test sites were covered. on the neck of the angel. 45 The gold seems to be applied with a thin mordant onto the original 37 This has led to the picture being described as being unfinished, but background paint, but without further research it is not possible it was probably just a pragmatic decision on the part of the artist to tell whether this is original or a later addition. who saw no need to try to apply more dark green paint (which 46 The pigments in both the salmon pink paint at the bottom of the would have been difficult to handle) on the small spaces between painting and the brighter, more orange, paint at the edges were the fingers when the underpaint was already providing a dark confirmed by EDX analysis on cross-sections from these areas. greenish tone, especially as the picture was to be placed high up 47 Confirmed by EDX analysis of cross-sections. in the altarpiece so would not be easily seen. 48 See for example L. Syson and R. Billinge, “Leonardo da Vinci’s use 38 The cross-section was analysed by SEM–EDX. The low proportion of of underdrawing in the ‘Virgin of the Rocks’ in the National Gallery Al in the red lake suggests that as in the flesh paint (which was and ‘St Jerome’ in the Vatican”, The Burlington Magazine, CXLVII, analysed by ATR–FTIR imaging) a proteinaceous lake pigment 1222, July 2005, pp. 450–63, note 12. prepared from dyestuff extracted from wool has been used. For a 49 See M. Spring et al. ‘Painting in Practice in Milan in the 1490s: discussion of this type of red lake pigment see Kirby et al. 2005 The Influence of Leonardo’, in this Bulletin, especially the section (cited in note 35). The red lake has an orange fluorescence in UV ‘General features of the technique and materials of the paintings’, light which is characteristic of madder. In addition angular particles pp. 78–112. that have the characteristic composition of soda lime silica glass 50 These diagrams are highly simplified attempts to summarise, in were identified. For discussion of glass see M. Spring, ‘Pigments in visual form, the results of the studies of the backgrounds in the sixteenth-century painting of the German School’, in The pictorial two paintings as described in the text. The colours used are based technique of Grünewald and his peers, P. Béguerie-De Paepe and on those identified in cross-sections or seen with a microscope M. Menu (eds), Musée d’Unterlinden, Colmar and C2RMF-CNRS, down cracks in the overpaint, but as these certain identifications 2007, pp. 136–144; and M. Spring, ‘Raphael’s materials: Some can only establish colour at particular points the boundaries new discoveries and their context within early sixteenth-century between different colours are for the most part highly speculative painting’, in Raphael’s Painting Technique: Working Practices before and should not be taken literally. It has not been possible to Rome, Proceedings of the Eu-ARTECH workshop organised by the determine the colour, or colours, used for the area outside the National Gallery and Eu-ARTECH, London November 11th 2004, incised lines on the Angel in Green, so this part of the diagram has ed. A. Roy and M. Spring, Quaderni di Kermes, Nardini Editore, been filled in with a neutral grey tone, which should not therefore 2007, pp. 77–86. be regarded as a representation of what was there originally. The 39 The presence of black in the shadows is borne out by the appearance positions of the current edges of the panels, including the later of the face in IRR, although they are not as dark in IRR as the additions, are drawn in blue in the diagrams. Within these blue shadows of the flesh of the Angel in Green. boxes the white lines indicate locations where incised lines, which 40 This paint mixture is quite different from that in the shadows of the relate to the original background, were found on the X-ray images. flesh of the Angel in Green, where the paint consists almost entirely These have been continued to complete the arcs (drawn in white, of charcoal black and red lake. In the Angel in Red the painter has although clearly there are no incisions to follow beyond the edge relied more on increasing the proportions of the red pigments to of the panel so the part above the blue line is speculative). The red give the darker shadows rather than adding large amounts of black outline in fig. 33 indicates the suggested original size of the panel pigment. In addition, it appears that a different red lake pigment for the Angel in Red as calculated from the grid (see fig. 7). On was used, since instead of the orange fluorescence suggestive of transposing this red outline onto the diagram for the Angel in madder dyestuff seen in the red lake in the Angel in Green, here the Green it was found that the completed incised arch fitted exactly, red lake has a pink appearance in ultraviolet light that points so this same outline has been used as a suggested original panel towards a pigment prepared from an insect dyestuff source. size in fig. 34. 41 As a result of this cracking a considerable amount of overpaint 51 Three samples exist from the outermost part of the arched structure has been applied to hide the exposed priming, which means that of the original background. However, they include only traces of some care needs to be taken when commenting on overall paint what might be original paint; in one case this seems to be pale handling in the red dress. grey, in another yellowish and in the third greenish. These traces 42 Plesters 1975 (cited in note 6). are so small that it is not possible to draw any firm conclusions 43 Analysis of samples from the grey niche of the Angel in Red by gas from them. chromatography identified the binding medium as walnut oil (see 52 Unfortunately the subsequent removal of most of this added wood Mills and White, cited in note 34). These early analyses did not means that any evidence to support such a theory, such as nails provide any indication as to whether the oil had been heat-bodied, or dowels, has been lost. but recent analysis of a sample from the grey niche on the Angel in Green by gas chromatography–mass spectrometry suggested that the walnut oil binder had been at least partially heat-bodied [A/P 1.3; P/S 3.0; A/Sub 4.0]. The pigments in the grey niche are lead white and what appears to be a black earth pigment of some type (as well as carbon, Al, Si and K were detected in significant quantity by EDX analysis indicating the presence of a silicate which suggests a natural mineral pigment). When examining the surface with a stereomicroscope, some particles with the shape of charcoal black were also seen. In two samples, there were one or two particles of the dark grey mineral galena (lead sulphide, PbS, identified by EDX). As so little is present it may be an impurity associated with one of the other pigments in the paint. It has not often been identified as a pigment, but has been reported on two Italian

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